Black holes (Astronomy)

Interview with Gerard 't Hooft, University Professor of Physics (Emeritus) at Utrecht University in the Netherlands. 't Hooft considers the possibility that the g-2 muon anomaly experiment at Fermilab is suggestive of new physics, and he reflects broadly on the current shortcomings in our understanding of quantum mechanics and general relativity. 't Hooft recounts his childhood in postwar Holland and the influence of his great uncle, the Nobel Prize winner Frits Zernike and his uncle, the theoretical physicist Nico van Kampen. He describes his undergraduate education at Utrecht University where he got to know Martinus Veltman, with whom he would pursue a graduate degree and ultimately share the Nobel Prize. 't Hooft explains the origins of what would become the Standard Model and the significance of Yang-Mills fields and Ken Wilson’s theory of renormalization. He describes Veltman’s pioneering use of computers to calculate algebraic manipulations and why questions of scaling were able to be raised for the first time. 't Hooft discusses his postdoctoral appointment at CERN, his ideas about grouping Feynman diagrams together, and how he became involved in quantum gravity research and Bose condensation. He explains the value in studying instantons for broader questions in QCD, the significance of Hawking’s work on the black hole information paradox, the holographic principle, and why he has diverged with string theorists. 't Hooft describes being present at the start of supersymmetry, and the growing “buzz” that culminated in winning the Nobel Prize. He describes his overall interest in the past twenty years in thinking more deeply about quantum mechanics and he places the foundational disagreement between Einstein and Bohr in historical context. At the end of the interview, 't Hooft surveys the limitations that prevent us from understanding how to merge quantum mechanics and general relativity and why this will require an understanding of how to relate the set of all integer numbers to phenomena of the universe.

Interview with Bruno Coppi, Professor of Physics Emeritus at MIT. Coppi recounts his childhood in Lombardi, Italy. He discusses his early interests in nuclear engineering and his graduate work in Milan on neutron transport theory. He explains the opportunities that led to his postgraduate appointment at the Princeton Plasma Physics Laboratory and his subsequent work at Stanford for his postdoctoral research in collision-less plasma. Coppi discusses his work at the Institute for Advanced Study where he interacted closely with Freeman Dyson, and he explains his decision to join the faculty at MIT where he could work with Bruno Rossi. He describes his collaborations in the Soviet Union with nuclear physicists, and he explains the sequencing of the Alcator program to the Ignitor program. Coppi describes the changes inherent in the AEC’s transformation into the DOE, and he explains the import of the Voyager 2 space mission. He describes his current interest in spontaneously rotating plasma and he reflects on why science is a humbling profession, even for geniuses. At the end of the interview, Coppi explains why the role of angular momentum remains profoundly mysterious, and why he is optimistic that he will continue to make contributions to the understanding of burning plasmas.

Interview with Alan Dressler, Astronomer Emeritus at The Carnegie Institute for Science Observatories. He describes his current focus on the James Webb Telescope and he conveys concern for a "post-reality" political environment that has taken a grip on American politics. He recounts his upbringing in Cincinnati, and how his curiosity about how things worked naturally pulled him toward astronomical interests. Dressler discusses his undergraduate education at UC Berkeley and his decision to pursue a PhD in the newly created Department of Astronomy at UC Santa Cruz. He describes the importance of the Lick Observatory for his research under the direction of Joe Wampler, and how Jim Peebles gave this thesis project a "seal" of approval. Dressler describes the origins of the Dressler Relation in his study of the morphology of galaxies and the density of their environment, and he describes the opportunities leading to his postdoctoral appointment at Carnegie. He explains the history of the Caltech-Carnegie partnership in astronomy, and he describes working with Allan Sandage and Jim Gunn. Dressler emphasizes the revolutionary effect the Hubble Telescope imparted to the field, and he discusses his time as a Las Campanas fellow. He describes how his work on galaxy formation fed into larger questions about the origins of the universe and the broader philosophical implication of our understanding of Earth's place in the universe. Dressler explains the Great Attractor Model and the state of play in black hole research in the 1980s, and he describes why he did not need to "see" an image of black holes to be convinced of their existence. He narrates the origins of the Association of Universities for Research and Astronomy, and the drama surrounding the repair of the Hubble. Dressler describes presenting the HST & Beyond report to NASA administrator Dan Goldin, and he discusses the natural progression for his work on the NASA Origins program. He discusses his subsequent focus on the Magellan Telescope and the EOS Decadal Survey. At the end of the interview, Dressler reflects on the strides made in galaxy formation research over the course of his career, and he conveys pride in playing a role in science, for which he appreciated since youth as a field that offered limitless opportunities to improve the world. 

Interview with Wendy Freedman, John & Marion Sullivan University Professor and senior member of the Kavli Institute for Cosmological Physics at the University of Chicago. She recounts her childhood in Canada, her early interests in science, and her decision to attend the University of Toronto, where she developed an interest in astronomy. She cites the Canada France Hawaii Telescope as the reason she stayed at Toronto for graduate school to work under the direction of Barry Madore. Freedman describes her postdoctoral appointment at Carnegie Observatories to work on the Cepheid distance scale, and she explains her decision to accept a position on the permanent staff at Carnegie. She narrates the origins of the Hubble Space Telescope Key Project, and she explains the resistance among theorists regarding the existence of the Hubble constant. Freedman discusses the importance of CCDs to measure the Hubble constant, and she marvels at Hubble’s long and productive life. She explains the inspiration for starting the Giant Magellan Telescope as an international collaboration, and she explains the opportunities that led to her becoming director of Carnegie. Freedman surveys the cooperative nature between the GMT and LSST projects and she projects optimism that GMT will propel fundamental advances in black hole research and for the search for exoplanets and possible for life beyond earth. She explains her decision to join the faculty at Chicago and she expresses pleasure at being able to work with students as a professor. At the end of the interview, Freedman reflects on the increasing complexity and expense of large-scale astronomy research and why it is important that the astronomy community relates its work and discoveries to the broader public.

Interview with John Hawley, John D. Hamilton Professor of Astronomy, and Senior Associate Dean for Academic Affairs in the College of Arts and Sciences at the University of Virginia. Hawley discusses his responsibilities as Associate Dean and he conveys his ongoing interest in black hole observational work and in the future findings of the James Webb Telescope. He reflects on his career’s overlap with the rise of computational astrophysics and he explains why he is agnostic on the hypothetical value of quantum computing to the field. He recounts his childhood in Maryland, then Kansas, and then northern California, in support of his father’s work as a minister, and he describes his undergraduate education at Haverford where he developed his interest in astronomy. Hawley explains his decision to work with Larry Smarr as his advisor at the University of Illinois, and he describes the origins of the Supercomputing Center. He describes the opportunities that led to him to Caltech to work with Roger Blandford, who was working on jets and active galaxies, and where he pursued synergies between analytic and computational analyses of black hole research. Hawley emphasizes the proximity to NRAO that influenced his decision to accept an offer from UVA, and he discusses his foundational collaboration with Steven Balbus on accretion disks. He explains his motivation to write the textbook Foundations of Modern Cosmology, what it was like to win the Shaw Prize, and how his administrative responsibilities gradually and mostly overtook his research agenda. At the end of the interview, Hawley reflects on the complementary nature of his technical collaboration with Balbus, and why he thinks terms of numerical and analytical approaches as separate endeavors.

Interview with Subir Sachdev, Herchel Smith Professor of Physics at Harvard University. Sachdev surveys his current research projects which includes a focus on Planckian metals and the Sachdev-Ye-Kitaev model, and he describes the interplay between theory and experiment on the topics he is following most closely. He describes the major advances in spin liquids research, and he recounts his childhood and Jesuit education in Bangalore. Sachdev discusses his undergraduate education at the Indian Institute of Technology and he explains the circumstances that led to his family’s emigration to the United States and his transfer to MIT where Dan Kleppner was a formative influence. He explains his decision to move to Harvard for graduate school, where David Nelson supervised his thesis research related to Nelson’s interests in developing the theory of the structure of metallic glasses. Sachdev describes his postdoctoral work on quantum spins and antiferromagnets at Bell Labs, and research advice he received from Bert Halperin. He explains his decision to join the faculty at Yale, he describes his key collaborations with Nick Read on quantum antiferromagnets and he narrates his increasing interest in cuprates. Sachdev discusses his decision to write Quantum Phase Transitions and he describes the origins of the SYK model and its relevance for black hole research. He discusses his involvement in string theory and his longstanding interests in Bose-Einstein condensation. Sachdev narrates his decision to transfer to Harvard and he describes his work in quantum chaos. He describes his professorship at the Tata Institute and the meaningfulness of being able to travel to and maintain contacts in India. At the end of the interview, Sachdev explains open issues in the theory of pseudo-gap in the high-temperature superconductors, how the SYK model may contribute to the development of a theory of quantum gravity, and he provides a long-range view of developments in the field of strange metals.

Interview with Roger Blandford, the Luke Blossom Professor at the School of Humanities and Sciences at Stanford University and Professor of Physics at SLAC. He discusses his current work developing alternate understandings of the Event Horizon Telescope image, on fast radio bursts, and on the notion that handedness has astrophysical origins. Blandford describes the history of cosmology as a respectable discipline within physics, and he credits the rise of VLBI in the 1960s and 1970s for demonstrating the evidence of black holes. He recounts his childhood in England, his early interests in science, and his education at Cambridge, where his thesis research on accretion discs and radio sources was supervised by Martin Rees. Blandford discusses his postdoctoral work on astrophysical particle acceleration and plasma and QED processes in pulsars and a formative visit to the Institute for Advanced Study and to Berkeley. He describes his initial impressions of Caltech where he joined the faculty and where he worked closely with Roman Znajek, and he explains the distinctions between radio jets and relativistic jets. Blandford explains his reasons for moving to Stanford to set up the Kavli Institute and he describes his involvement with the Astronomy and Astrophysics Decadal Survey. At the end of the interview, Blandford contends that the most exciting developments in the field have been on exoplanet research, why the possibilities in astrobiology give him cause for optimism, and why the concept that astronomical discovery arrives as “logically unscripted” resonates with him.

Interview with Sheperd Doeleman, an astronomer at the Harvard Smithsonian Center for Astrophysics, founding member of the Black Hole Initiative, and founding director of the Event Horizon Telescope. He surveys his global initiatives and his interest in fostering black hole research in Africa and he describes how the pandemic has slowed down his work. Doeleman affirms that he is of the generation for which black holes were always “real” and not theoretical abstractions, and he provides a history of the discovery that supermassive black holes were at the center of galaxies. He reflects on the applied science that was achieved in the course of creating EHT, and he describes the unique values that land and space-based telescopes offer. Doeleman recounts his childhood in Oregon and his admission to Reed College when he was fifteen. He explains his motivations in completing a solo research mission in Antarctica and he describes the opportunities that led to his graduate research at MIT, where he worked with Alan Rogers at the Haystack Observatory on the 3mm VLBI. Doeleman narrates the technical advances that allowed his team to achieve an eight-fold increase in bandwidth, and he describes the EHT’s administrative origins and the events leading to the measurement of the Sagittarius A* black hole. He describes what it meant to image the black hole, and he conveys the deep care and caution that went into the analysis before EHT was ready to publicize its findings. Doeleman discusses winning the Breakthrough Prize as the public face of a large collaboration, and at the end of the interview, he considers the ways that EHT’s achievement can serve as a launchpad to future discovery.

Interview with Stuart Shapiro, Professor of Physics and Astronomy at the University of Illinois at Urbana-Champaign. Shapiro discusses the relationship between physics and astronomy at Illinois and the shifting boundaries between cosmology, astrophysics, and astronomy. He recounts his childhood in Connecticut and his fascination with the space race. Shapiro describes his undergraduate experience at Harvard in the late 1960s and the import of the discovery of the cosmic wave background. He explains his interest in general relativity as the motivating factor for his choice of Princeton for graduate work, where he worked under the direction of Jim Peebles on gas accretion onto black holes. Shapiro describes his postdoctoral appointment at Cornell and the formative collaboration he developed with Saul Teukolsky. He describes the computational advances that propelled the field of numerical relativity and how his interactions with Kip Thorne provided an early entrée to the LIGO endeavor. Shapiro explains how he and Teukolsky challenged the cosmic censorship hypothesis and how Penrose responded to this challenge. He explains his decision to join the faculty at Illinois where he continued to work on neutrino astrophysics and the prospects for observation of hypermassive neutron stars. Shapiro explains his motivations in writing "Numerical Relativity" and he compares his reactions to the detection of gravitational waves with LIGO and the imaging of a black hole with the Event Horizon Telescope. At the end of the interview, Shapiro surveys his current interests in the dynamical problems associated with dark matter. He also conveys his deep love of sports and some unlikely coincidences he has experienced in his many years of being a fan.

Interview with Stephen Fulling, Professor of Mathematics and of Physics and Astronomy at Texas A&M University. Fulling explains the history of why his primary academic department is math and how the field of general relativity became more directly relevant to observational cosmology in the 1960s and 1970s. He recounts his middle-class upbringing in Indiana and his dual interests in math and physics which he developed during his undergraduate years at Harvard. Fulling discusses his graduate work at Princeton, where Arthur Wightman supervised his research. He explains the contemporary controversy over the Casimir effect and his interest in the Minkowski vacuum, and he discusses his postdoctoral appointment at UW-Milwaukee. Fulling describes his work on Riemannian spacetime and Robertson-Walker spacetime, and he explains the opportunity that led him to the University of London, where black holes was a focus of research. He describes meeting Paul Davies and Chris Isham and how the field started to take black holes seriously as observable entities in the 1980s. Fulling explains his longstanding interest in asymptotic expansion and he surveys more recent advances in the Casimir effect. He reflects on the Unruh effect as it approaches its 50th anniversary, and he addresses the disagreement on whether or not it has been observed and whether the Unruh effect implies Unruh radiation. At the end of the interview, Fulling discusses his current interests in the soft wall problem and acceleration radiation, and he explains his ongoing interest in seeing advances in research on Casimir energy.